It's something of a departure from his other works, but Jon Krakauer's Under the Banner of Heaven: A Story of Violent Faith is a very intriguing and very disturbing book. If you're interested in religions and religious belief, as I've always been, it's definitely worth a look.

The story begins with Ron and Dan Lafferty's brutal murder of their sister-in-law and year-old niece, which they claimed was ordered by God. Intercut with the story of this crime is an account of the founding of Mormonism, which is marked by violence committed both by and against the Mormons.

Most disturbing of all is Krakauer's investigation into "Mormon fundamentalism" and the polygamous communities where it is still practiced, and where as a consequence sexual abuse and incest run rampant. The effects on the young women (sometimes as young as 13) who are made "spiritual wives" to men more than twice their ages are nearly too horrible to contemplate.

Krakauer ends his book with an account of the trial of the Lafferties, organized around one very difficult question: In a society where 90% of the population professes a belief in God, and nearly as many believe in the existence of angels and the efficacy of prayer, how can we differentiate between spiritual beliefs? What makes a belief in transubstantiation "rational" and "normal," but a belief in demon possession "irrational" and "crazy"? Where, and how, can we draw the line?

This is a deceptively difficult question, with no easy answer.

Good book.